New research shows that the humble aspirin can reduce the long-term risk of risk of colorectal cancer in people with a family history of Lynch syndrome by about 60 percent, according to an article published in the Oct. 28 issue of The Lancet Genetics.

Henry Lynch, M.D., professor of medicine and director Creighton University Hereditary Cancer Center, is a study co-author and chair of the multinational steering committee that conducted the study. Lynch first identified Lynch Syndrome (named after him), also known as hereditary nonpolyposis colorectal cancer, in the 1960s.

“This is an incredibly important finding,” Lynch said. “We finally have a way to help people reduce their risk of getting colorectal cancer from Lynch syndrome. However, this is not a substitute for regular colonoscopies.”

The study, led by John Burn, M.D., professor at Newcastle University, United Kingdom, looked at 846 men and women at risk of Lynch syndrome who participated at 43 medical centers in 16 countries. The international team’s findings dispute a 2008 report by the same group, which said aspirin did not prevent hereditary colorectal cancer.

“What we found in this latest study (which involved the same patients) is that aspirin has a major preventative effect on cancer, but the benefits appear several years after one begins taking aspirin,” Lynch said.

While some of the health benefits of aspirin have been known for years, the new findings are the first from a randomized controlled trial looking at the effect of aspirin on cancer, he said.

The research, conducted between 1999-2007, focused on 861 people who either took two aspirins (600 mg) daily for two years or a placebo. At the end of the treatment stage in 2007, there was no statistically significant difference in cancer incidence between those who took aspirin and those who had not.

However, the researchers conducted a follow-up study on the same patients. They found that by 2010, there were 19 new colorectal cancers among those who had received aspirin and 34 among those on placebo. The incidence of cancer among the group using aspirin was about half that of those not using aspirin – about five years after patients started taking the aspirin.

Further analysis focused on the patients who took aspirin for at least two years following the original study design - about 60 percent of the total. Here the effects were even more pronounced. A 63 percent reduced incidence of colorectal cancer was observed with 23 bowel cancers in the placebo group but only 10 in the aspirin group.

Looking at all cancers related to Lynch syndrome, almost 30 percent of the patients taking the placebo developed cancer, compared to around 15 percent of those taking aspirin.

Lynch syndrome is an inherited genetic disorder affecting genes responsible for detecting and repairing damage in the DNA. It has been linked to a number of hereditary forms of cancer, including colorectal, endometrium, ovary, stomach, small bowel and urologic, and, most recently, prostate and breast. Hereditary colorectal cancer resulting from the syndrome accounts for one in every 35 U.S. colorectal cancer cases and is the most common hereditary form of the disease.

Before taking aspirin on a regular basis, patients should consult with their doctors, since aspirin has been known to result in stomach problems, including bleeding in the gastrointestinal tract, Lynch stressed.

He recommends that persons at risk of the cancer should continue to undergo colonoscopies biannually between the ages of 25 and 40 and annually after that.

The international team is preparing a large-scale follow-up trial and want to recruit 3,000 people across the world to test the effect of different doses of aspirin. The trial will compare two aspirin a day with a range of lower doses to see if the protection offered is the same. For more information on the trial, visit www.capp3.org or contact the Creighton Hereditary Cancer Institute at 402.280.2634.